Summary of Work: We are conducting a study to estimate prevalence and risk factors for uterine fibroids (as detected by a standard transabdominal and transvaginal ultrasound examination) in black women compared to nonblacks aged 35-49. Uterine tissue from women having fibroids removed will be studied to identify hormonal charaacteristics, growth factors and genetic changes in the tissue that are associated with fibroid development. Data have been collected from approximately 1500 women randomly identified from 35-49 year old members of a health care plan that serves approximately equal numbers of blacks and whites. A telephone interview was used to collect information on demographic factors, medical history, dietary intake, reproductive history, life style factors, and occupational/environmental exposures. Blood was collected (after fasting) in order to measure lipids, insulin, and potential susceptibility genes. Urine was collected to measure endogenous gonadotropins. Blood pressure, heart rate, weight, height, and waist-to-hip ratio were measured. Medical record data provide some minimal descriptive information on nonresponders. Tissue from surgical specimens will be analyzed for growth factors, hormonal conditions, and genetic characteristics of the fibroid. - fibroids, risk factors, prevalence, uterus, leiomyoma - Human Subjects & Human Subjects: Interview, Questionaires, or Surveys Only